Process of producing wrinkle resistant cellulose fabrics of relatively high moistureregain



United States Patent PROCESS OF PRODUCING WRINKLE RESISTANT CELLULOSEFABRICS 0F RELATIVELY HIGH MOISTURE REGAIN Clifford M. Moran and SidneyL. Vail, New Orleans, and Russell M. H. Kullman, Metairie, La.,assignors to the United States of America as represented by theSecretary of Agriculture No Drawing. Filed Sept. 27, 1962, Ser. No.227,641

14 Claims. (Cl. 8-1163) (Granted under Title 35, US. Code (1952), see.266) A non-exclusive, irrevocable, royalty-free license in the inventionherein described, throughout the world for all purposes of the UnitedStates Government, with the power to grant sublicenses for suchpurposes, is hereby granted to the Government of the United States ofAmerica.

This invention relates to the treatment of cellulosic textile materials,particularly cellulose fabrics, to produce textiles having improvedproperties. In this invention and in copending application Serial No.204,013, filed June 20, 1962, now US. Patent 3,198,660 of Sidney L.Vail, John G. Frick, Jr., and Wilson A. Reeves and c0- pendingapplication Serial No. 21 1,141, filed July 19, 1962,

now US. Patent 3,160,469 of Sidney L. Vail, Clifford M.

Moran, and John D, Reid, new textile treating agents and their use aredescribed. The fabrics produced in these inventions are resistant towrinkling, have improved resiliency, and possess washwear properties.For convenience, such fabrics are referred to in this application asWrinkle resistant, or as possessing wrinkle resistance properties.Moreover, the finishes produced from the new textile treating agents ofthese inventions were found to be extremely durable to acid hydrolysis.More specifically, the present invention relates to production ofdurable, Wrinkle resistant cellulosic fabrics, whereby these treatedcellulosic fabrics possess, in addition, the property of moisture regainto an extent equal to or slightly less than the cellulosic fabric priorto treatment.

The production of commercial, wrinkle resistant cellulosic fabrics(cotton cellulose for the most part) is generally accomplished by theuse of diand polyfunctional N-methylolamide reactants which areconsidered to crosslink cellulose. The cellulosic fabrics produced bythis process generally have significantly lower moisture regain than thecellulosic fabrics before treatment. That is, cellulosic fabrics treatedto impart wrinkle resistance, when driegl to remove essentially all thewater, will regain less moisture than the same cellulosic fabric thathas not been treated when both fabrics are exposed to normal moisture inthe atmosphere. Standard atmospheric conditions of 65% relative humidityand 70 F. are often used for the purpose of determining moisture regain.

It is desirable for several reasons that a wrinkle resistant cellulosictextile have moisture regain values approximately equivalent to orhigher than that of the same textile before treatment. First, thecomfort factor of cellulosic fabrics is related directly to moistureregain. Any reduction in moisture regain of a cellulosic fabric due to awrinkle resistance finish would therefore reduce the comfort factor.Secondly, undesirable generation of static electricity is relatedinversely to the hygroscopic nature of the elements comprising thefabric. Thus, it is desirable to avoid loss in moisture regain when awrinkle resistant fabric is produced. Presumably, other factors such asdyeability, soiling, etc. are also affected by the property of moistureregain.

A primary object of the invention is to provide a process for thetreatment of cellulose fabrics with amide-type compounds and theN-methylol derivatives of these amidetype compounds, whereby the fabricacquires the properties of increased resiliency and wrinkle resistancewithout sacrificing excessive loss of moisture regain. It is,furthermore, an object of this invention to provide such a treatmentwhereby the finish produced is resistant to harsh conditions of acidichydrolysis. Also, the modified fabrics may be laundered repeatedly byordinary procedures, which procedures may include the use ofhypochlorite bleaching agents, without suffering discoloration. It is afurther object to produce a finish which is not susceptible to chlorinedamage from ironing after the modified fabric has been treated withhypochlorite bleaching agents.

In general, these and other objects of the invention are accomplished bytreating, as by impregnation, the cellulosic textile material,particularly a cellulose fabric, with an aqueous solution containing (a)about from 5 to 20 weight percent of an amide-type compound having thefollowing structure:

wherein R and R are the same or different alkyl groups containing from 1to 4 carbon atoms; or the mono-N- methylol derivatives of theseamide-type compounds having the structures:

i I i t RfiN(| Ht|JHNfiR or R0fiNCH-CHN-COR 0 OH OH 0 OH OH 0 Structure0 Structure 1) wherein R and R have the same significance as above and Xand Y are unlike members of the group consisting of hydrogen and CH OH;or the di-N-methylol derivatives of these amide-type compounds havingthe structures:

wherein R and R have the same significance as above, and (b) from about0.5 to 5 weight percent of an acidic catalyst, such as magnesiumchloride, zinc fiuoborate, zinc nitrate, and a mixture consisting ofweight percent of citric acid and 40 weight percent of magnesiumchloride hexahydrate, and dry curing the treated cellulosic textilematerial with heat.

From prior work disclosed in the aforementioned applications it wasindicated that the finish derived from compounds of Structure A would besusceptible to chlorine damage on ironing, whereas the finish derivedfrom Structure B would not. As shown in Example 2 of this application,this was shown to be true and limits the use of derivatives of compoundsof Structure A to treatment of fabrics where susceptibility to chlorinedamage on ironing is not critical.

The compounds of Structures A and B, without methylolati-on, contain twoN-methylol groups and, therefore, should theoretically be difunctional.However, it was found that a more effective agent was obtained byreacting the compounds with formaldehyde to obtain the N-methylolatedderivatives designated by Structures C, D, E, and F.

The N-methylolated derivatives used for the treatment of the cellulosictextile in the process of this invention can be obtained by the reactionof the compounds of the abovedescribed Structures A and B andformaldehyde in aqueous media under alkaline conditions. It ispreferable with compounds of Structure B to use an excess offormaldehyde in this reaction, the excess being about one to two molarequivalents of free formaldehyde based on the presumption that all amidoNH groups will methylolate to form N-methylol groups. Thus, although twomolar equivalents of formaldehyde could theoretically fully methylolatethe compounds of the above-described structures, it is preferable tohave about three to four molar equivalents of formaldehyde for thereaction with the compound. The chemical efifect of the excessformaldehyde is not definitely known; however, in general, it appearsthat some formaldehyde is reacting with the cellulose to form methyleneether crosslinks in addition to the crosslinking through the nitrogenousagent. An amount of formaldehyde significantly in excess of the four toone ratio can also be employed, but it is inefficient and uneconomicalto use such a large excess. With compounds of Structure A only anequimolar ratio of formaldehyde to the bisamide is required. The othercondi tions of this reaction are well-known in the trade. Generally,heating the alkaline, aqueous solution of the compounds of theabove-described Structures A and B and formaldehyde at 60 C. for 30minutes or allowing the solution to stand at room temperature (20-25"C.) for 1824 hours is sufiicient to achieve formation of the N-methylolderivatives. The reaction products thus produced are water soluble. Thesolution can be used as is or can be diluted with water for treatment ofthe cellulosic material.

Prior to application of the agent to fabric, an acidic substance or asubstance producing acidity at elevated temperatures is added to thediluted solution to serve as a catalyst. The concentration of thereactants, i.e., the formaldehyde adducts of compounds of Structure A orB plus the excess or unreacted formaldehyde, can be varied depending onthe particular textile processing conditions used, the type of textilebeing treated, and the properties desired in the finished textile.Generally, it is preferred to use from about 5% to 20% by weight of thereactants in the diluted treating solution. The catalysts which may beused are well-known in the trade. Magnesium chloride, zinc fluoborate,and zinc nitrate are examples of particularly suitable catalysts.Another such catalyst consists of 60 weight percent of citric acid and40 weight percent of magnesium chloride hexahydrate. From about 0.5% toabout 5% by weight of the acidic catalyst is generally preferred.

Treatment of the cellulosic textile material is carried out by standardprocedure. The textile is thoroughly wetted with the above-describedtreating solution; the excess liquid is mechanically removed, and thewetted textile is dried and cured. Following the curing operation, it ispreferable but not absolutely necessary, to water-wash the treatedtextile in an alkaline solution to remove any unreacted materials.

The processes of this invention can be used to treat substantially anyhydrophilic fibrous cellulosic material such as cotton, rayon, ramie,jute and the like which can be impregnated with a liquid, dried, andcured.

The following examples are given by way of illustration and not by wayof limitation of the invention. The detailed procedures given below inthe examples are illustrative, and are not the only or specificconditions for the production of an acceptable finished textile. Manyvariations or additions within these procedures can be made, as will bereadily apparent to those skilled in the art. In the examples, all partsand percentages are by weight. The fabrics were tested by the followingmethods: Wrinkle recovery angle, Monsanto method, American Society forTesting Materials (ASTM) test D 1295-53T; breaking strength, ASTM test D39-49; damage caused by retained chlorine, American Association ofTextile Chemists and Colorists tentative test method 92-1958T. Alltextile data were obtained on the warp threads only,

EXAMPLE 1 A weighed portion of the appropriate compound as listed belowwas dissolved in a 1:1 mixture of water and dimethylformarnide. The pHof the solution was checked,

and, when necessary, aqueous sodium hydroxide was added to adjust the pHto a value of about 7. Then a weighed portion of zinc fluoborate wasadded such that its final concentration in the padding solution wasabout 1%. Concentration of the crosslinking reactant in the paddingsolution was about 7.5%. Using this general procedure, the followingcompounds were used to prepare padding solutions:

Solution 1. Dihydroxyethylene bisacetamide Solution 2. Dihydroxyethylenebisurethane A sample of x 80 cotton print fabric, scoured, desized, andbleached, was dipped in the treating solution and padded between rollersto give a 70 to 80% increase in the weight of the fabric. The wet fabricwas pinned to original dimensions, dried for 10 minutes at 60 C. andcured for 3 minutes at C. This treatment was followed by a wash in warm,alkaline water with a nonionic detergent added, and then the fabric wastumble dried.

Also, a 5% aqueous solution of dihydroxyethylene bisacetamide (Solution1A) and a 5% aqueous solution of dihydroxyethylene bisurethane (Solution2A), each containing 1.2% citric acid and 0.8% magnesium chloridehexahydrate as catalyst, were prepared. It was necessary to warm thewater to dissolve the bisamides. However, once dissolved, the bisamidesremained in solution until after the fabrics were treated. Usingconditions similar to the above, treated fabrics were obtained fromSolution 1A with a wrinkle recovery angle (warp only) of 131. In asimilar manner, Solution 2A produced a treated fabric with a wrinklerecovery angle (warp only) of 118.

EXAMPLE 2 A weighed portion of the appropriate compound as listed belowwas dissolved in an alkaline, aqueous solution of formaldehyde, suchthat the molar ratio of formaldehyde to the bisamide was 3:1 or as notedotherwise. The pH of the solution was checked, and, when necessary,aqueous sodium hydroxide was added to adjust the pH to a value of about8. The solution was allowed to stand for 24 hours at 20-25" C. or heatedfor one hour at 60 C. Then a weighed portion of magnesium chloridehexahydrate was added such that its final concentration in the paddingsolution was about 4%. Concentration of the unmethylolated, nitrogenousagent in the padding solution was about 5%. Using this generalprocedure, with variations noted where appropriate, the followingcompounds were used to prepare various padding solutions:

Solution 3. Dihydroxyethylene bisacetamide.

Solution 4. Dihydroxyethylene bisacetamide with a catalyst of 1% zincfiuoborate.

Solution 5. Dihydroxyethylene bisurethane.

Solution 6. A 10% concentration of dihydroxyethylene bisurethane.

Solution 7. Dihydroxyethylene bisacetamide with a molar ratio offormaldehyde to bisamide of 1:1.

Solution 8. Dihydroxyethylene bisurethane with a molar ratio offormaldehyde to the bisamide of 1: 1.

A sample of 80 x 80 cotton print-fabric was treated as described inExample 1, except that the fabric was dried for seven minutes at 60 C.The properties of the treated fabrics are shown in Table 1.

EXAMPLE 3 The durability of some of the finishes to acidic hydrolysiswas tested by treating the fabrics for thirty minutes at 80 C. in asolution containing 1.5% phosphoric acid and 5% urea. Also, a fabricprepared in the usual manner from a dimethylolurea (DMU) solution washydrolyzed for comparison purposes. The results of this hydrolysis onproperties of the treated fabrics are given in Table II.

Table I PROPERTIES OF TREATED FABRICS Breaking Strength Fabrics fromSolution Wrinkle Recovery Retained after Angle (warp only) Scorch Test,Percent 105 22 09 70 138 34 128 21 136 100 127 90 130 26 8 112 73Untreated 75 95 T able Il ACID HYDROLYSIS OF TREATED FABRICS Percent ofOriginal Wrinkle Recovery Fabrics from Solution Nitrogen Retained Anglealter Alter Hydrolysis Hydrolysis EXAMPLE 4 The moisture regain of someof the treated fabrics was determined in the following manner: (1) thesample was heated to 100 C. for minutes (2) then placed in aconditioning atmosphere of 70 F. and 65% relative humidity for 72 hours(3) the sample was weighed (4) then dried in oven at 100 C. for 4 hours(5) and reweighed.

Percent moisture regain:

Conditioned we1ghtdry weight X 100 dry Weight For comparison purposes,the moisture regains of a sample of dimethylolurea (DMU) treated fabricand an untreated fabric were determined.

The results are shown in Table III.

1. The process comprising impregnating a cellulose fabric with anaqueous solution containing about from 5 to weight percent of a compoundof the formula wherein R and R are alkyl groups containing from 1 to 4carbon atoms and X and Y are unlike members selected from the groupconsisting of hydrogen and CI-I OH, and from 0.5 to 5 weight percent ofan acidic catalyst, and dry curing the impregnated cellulose fabric withheat.

2. The process of claim 1 wherein R and R are diiferent alkyl groups.

3. The process of claim 1 wherein R and R are the same alkyl group.

4. The process of claim 3 wherein R and R are methyl and the acidiccatalyst in Zn(BF 5. The process of claim 3 wherein R and R are methyland the acidic catalyst is Mgcl 6. The process comprising impregnating acellulose fabric with an aqueous solution containing about from 5 to 20weight percent of a compound of the formula wherein R and R are alkylgroups containing from 1 to 4 carbon atoms, and from 0.5 to 5 weightpercent of an acidic catalyst, and dry curing the impregnated cellulosefabric with heat.

7. The process comprising impregnating a cellulose fabric with anaqueous solution containing about from 5 to 20 weight percent of acompound of the formula wherein R and R are alkyl groups containing fromi to 4 carbon atoms and X and Y are unlike members selected from thegroup consisting of hydrogen and CH OH, and from 0.5 to 5 weight percentof an acidic catalyst, and dry curing the impregnated cellulose fabricwith heat.

8. The process comprising impregnating a cellulose fabric with anaqueous solution containing about from 5 to 20 weight percent of acompound of the formula wherein R and R are alkyl groups containing from1 to 4 carbon atoms, and from 0.5 to 5 weight percent of an acidiccatalyst, and dry curing the impregnated cellulose fabric with heat.

9. The process of claim 8 wherein R and R are different alkyl groups.

10. The process of claim 8 wherein R and R are the same alkyl group.

11. The process of claim 10 wherein R and R are ethyl and the acidiccatalyst is Zn(BF 12. The process of claim 10 wherein R and R are ethyland the acidic catalyst is MgCl 13. The process comprising impregnatinga cellulose fabric with an aqueous solution containing about from 1 to 5weight percent of dihydroxyethylene bisurethane and from 0.5 to 5 weightpercent of an acidic catalyst, and dry curing the impregnated cellulosefabric with heat.

14. The process of claim 13 wherein the acidic catalyst consists of 60weight percent of citric acid and 40 weight percent of magnesiumchloride hexahydrate.

References Cited by the Examiner UNITED STATES PATENTS 3,090,665 5/1963- Parsons et a1 8-1 16.3 3,160,469 12/1964 Vail et al 8116.33,185,539 5/1965 Madison et a1 8116.3

NORMAN G. TORCHIN, Primary Examiner.

H. WOLMAN, Assistant Examiner.

1. THE PROCESS COMPRISING IMPREGNATING A CELLULOSE FABRIC WITH ANAQUEOUS SOLUTION CONTAINING ABOUT FROM 5 TO 20 WEIGHT PERCENT OF ACOMPOUND OF THE FORMULA
 6. THE PROCESS COMPRISING IMPREGNATING ACELLULOSE FABRIC WITH AN AQUEOUS SOLUTION CONTAINING ABOUT FROM 5 TO 20WEIGHT PERCENT OF A COMPOUND OF THE FORMULA
 7. THE PROCESS COMPRISINGIMPREGNATING A CELLULOSE FABRIC WITH AN AQUEOUS SOLUTION CONTAININGABOUT FROM 5 TO 20 WEIGHT PERCENT OF A COMPOUND OF THE FORMULA
 8. THEPROCESS COMPRISING IMPREGNATING A CELLULOSE FABRIC WITH AN AQUEOUSSOLUTION CONTAINING ABOUT FROM 5 TO 20 WEIGHT PERCENT OF A COMPOUND OFTHE FORMULA